// @file scalarencoding.cpp Represents and defines scalar-encoded plaintext
// objects in Palisade.
// @author TPOC: contact@palisade-crypto.org
//
// @copyright Copyright (c) 2019, New Jersey Institute of Technology (NJIT)
// All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution. THIS SOFTWARE IS
// PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
// EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "encoding/scalarencoding.h"

namespace lbcrypto {

bool ScalarEncoding::Encode() {
  if (this->isEncoded) return true;
  PlaintextModulus mod = this->encodingParams->GetPlaintextModulus();

  if (value <= LowBound() || value > HighBound())
    PALISADE_THROW(config_error,
                   "Cannot encode integer " + std::to_string(value) +
                       " because it is out of range of plaintext modulus " +
                       std::to_string(mod));

  auto entry = value;

  // map to -p/2 .. p/2
  if (value < 0) {
    entry += mod;
  }

  if (this->typeFlag == IsNativePoly) {
    this->encodedNativeVector.SetValuesToZero();
    this->encodedNativeVector[0] = entry;
  } else {
    this->encodedVector.SetValuesToZero();
    this->encodedVector[0] = entry;
  }

  if (this->typeFlag == IsDCRTPoly) {
    this->encodedVectorDCRT = this->encodedVector;
  }

  this->isEncoded = true;
  return true;
}

bool ScalarEncoding::Decode() {
  this->value = this->typeFlag == IsNativePoly
                    ? this->encodedNativeVector[0].ConvertToInt()
                    : this->encodedVector[0].ConvertToInt();

  PlaintextModulus mod = this->encodingParams->GetPlaintextModulus();

  if (this->value > int64_t(mod / 2)) this->value -= mod;

  return true;
}

} /* namespace lbcrypto */
